To handle their varied washing needs, restaurants and other establishments having commercial kitchens typically are equipped with automatic dishwashers for handling the conventional flow of dishes, silverware and glassware. The facts that these machines handle relatively consistent loads, operate with a constant volume of water and are automated combine to make it relatively easy to accurately control the amount of wash chemicals these dishwashers use. Thus, through the use of sensors, flow regulators and other electronic devices, these machines can be set up to dispense wash chemicals, such as detergents, rinse aids and the like, in appropriate amounts to be effective without excessive use. As a result, these dishwashing machines enable the wash chemicals to be used in an efficient and economical manner.
Most commercial kitchens are also equipped with one or more sinks for manually washing small volumes of dishes and more cumbersome items such as pots and pans. The volume of the detergent solution required for such operations is typically determined by the size and quantity of the objects to be washed and the volume of the washing vessel. At times, the particular washing task may require that the sink be substantially filled with detergent solution, while at other times a much smaller volume of detergent solution may be needed.
In a typical manual washing operation, the amount of detergent used to form the washing solution is at the sole discretion of the operator. For example, the operator normally will place a quantity of detergent in the sink and then fill the sink with a desired volume of water. In many instances, the amount of detergent used will bear no relation to the volume of water added to the sink. As a result, the washing solution may contain too little detergent to clean properly or, as is more frequently the case, an excessive amount of detergent may be used than is necessary for the specific job. Thus, the very nature of these manual washing operations makes it difficult to control the amount of detergent and other wash chemicals consumed in these processes.
Attempts have been made in the past to add some degree of control to the quantity of wash chemicals used by the operators in these manual washing procedures. One approach designed specifically for dispensing liquid detergents employs a venturi-type proportioner to dispense the liquid detergent in a predetermined proportion relative to the fill water for the sink. In this device, as the fill water passes the liquid detergent dispenser it creates a certain level of vacuum which draws an appropriate amount of liquid detergent into the water flow--the faster the water flow, the more detergent is drawn in and the slower the water flow, the less detergent is drawn in so that the proportion of liquid detergent to fill water remains substantially constant.
Recent advances in the detergent industry have led to the development of solid wash chemical capsules consisting of a block of a wash chemical solidified within a jar or other container. Ease of handling, long shelf life, premium quality, uniform solubility and reduced shipping costs have caused these wash chemicals to become extremely popular. In order to dispense these solid chemicals, dispensing systems have been developed which spray a solvent, such as water, against the solid block, whether the block remains within its container or has been removed therefrom, to form a concentrated solution. The concentrated solution runs out of the dispenser into a reservoir or may be sent directly through a conduit for use in a dishwasher. When the chemical substance within the container has been completely dissolved, the dispenser can be recharged by simply removing the empty container and inserting a new container in its place. Dispensers of this type are disclosed in U.S. Pat. Nos. 4,687,121, 4,690,305 and 4,999,124 to Copeland, and U.S. Pat. Nos. 4,426,362 and 4,826,661 to Copeland et al.
The dispensers which heretofore have been available have dispensed these solid wash chemicals in the form of concentrated solutions which must be further diluted prior to use. Since these devices are usually used in connection with an automatic dishwashing machine, this ordinarily would not present a problem because, as noted above, it is relatively easy to accurately control the amount of wash chemicals used by automatic dishwashers. Problems arise, however, when these dispensers are used to dispense solid-form wash chemicals for use in manual washing operations. In this situation, an operator can fill a sink or other receptacle with as much of the concentrated wash chemical solution as desired and may or may not dilute the concentrated solution with additional water prior to use. Even when the operator does so dilute the concentrated solution, the lack of control makes it difficult to assure that the right amount of water has been added to dilute the concentrated solution to an appropriate use concentration. As a result of these difficulties, businesses which employ solid wash chemicals in manual washing operations are unable to accurately predict the rate at which these wash chemicals are being used and therefore encounter problems maintaining an adequate inventory of these chemicals. More importantly, since the concentration of the solution will affect cleaning performance, the inability to effectively control solid chemical use makes it difficult to obtain optimum cleaning.
In an attempt to better control the amount of concentrated solution dispensed by these devices, efforts have been made to incorporate timers into the devices to limit the dispensing cycle. The cost of these timers, the unavailability of electricity and the need for frequent maintenance have made this approach less than desirable. Moreover, since the operator can actuate the timer as often as he pleases while a receptacle is being filled, this approach effectively provides no control of chemical use at all. Further, these timers frequently are set up so that once actuated they fill the entire wash vessel with a fixed amount of solution, and therefore often dispense more solution than is needed for smaller washing jobs. Hence, the detergent industry has generally failed to provide an effective and inexpensive solution to the problem of controlling the dispensing of solid-form wash chemicals and, more particularly, the dispensing of these chemicals in a concentration which is ready for use.
There therefore exists a need for a dispensing device which is capable of controlling the use of solid-form wash chemicals so that solutions having a desired concentration for use can be provided on a consistent basis. Preferably, such dispenser will dispense a dilute solution of the wash chemical which is ready for immediate use without any further adjustment in concentration.